Drawing instrument



(ModeL) needle-points.

side elevation of the leg carrying the needle:

UNITED STATES PATE T OFFICE.

tIOHN A. BERGSTROM, OF PASSAIC, NEW JERSEY.

DRAWING INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 605,692, dated June 14, 1898. Application filed November 13, 1897. Serial No. 658,475. (ModeL) To all whom itmay concern:

Be it known. that I, JOHN A. BERGSTROM, of Passaic, in the county of Passaic and State of New Jersey, have invented a new and Improved Drawing'Inst'rument, of which the following is a full, clear, and exact description.

The invention relates to compasses and dividers and its object is to provide a new and improved drawing instrument arranged to permit ordinary adj ustment and a secondary adjustment and independent yielding of the legs for accurate-measurement and for proper shading of curved lines.

The invention, consists of novel features and parts and combinations of the same, as will hereinafter be more fully described, and pointed out in the claims.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the figures.

Figure 1 is a side elevation of the improvement as appliedto a compass with pen and Fig. 2 is an enlarged sectional point. Fig. 3 is a like View of a modified form of the same, and Fig. 4 is a plan view showing circles shaded with the instrument.

The improved drawing instrument illustrated in Figs. 1 and 2 is provided withlegs A and B, pivotally connected with each otherby a pivot O, the leg A carrying a pen D and the leg 13 carrying a needle-point E. The connection between the needle-point E and the leg B is, by means of a flat spring F, riveted or otherwise fastened at its upper end to the leg B at the inside thereof and near the pivot O. The spring F is engaged by an adjusting-screw G, passing loosely through the leg B, and between the latter and the head of the screw G is interposed a spring H, preferably coiled around the shank of the screw and set in a recess B, formed in the said leg, as is plainly shown in Fig. 2. g

The second spring may be in the form of a flat spring H, similar to the spring F, carrying the needle-point E and fastened by the same means to a leg 13 as shown in Fig. 3, the difierence being that the springs F and H are located on opposite sides of said leg.

Now it is evident that by the arrangement described the pivot 0 permits of moving the legs A and B toward or from each other for .the usual adjustment'and for maintaining the legs in this adjustment. I

The point E, and with it the leg B, is rendered capable of fiexure'in either direction toward or from the otherleg A by the springs F and H or by the springs F and H, as shown in the modified form in Fig. 3. By screwing up the adjusting-screw G or unscrewing the samev in the spring F the tensions of the springs H and F can be regulated relative to each other to permit more or less fiexure of the point E and in opposite directions toward and from the other leg A after the usual adjustment is made to move the pen D, for instance, farther from or nearer to the point of the needle-point, according to the work at hand. If the device is applied to ordinary dividers, the legs A and B are first adjusted to bring the points of the legs approximately to the distance to be measured, and then the operator turns the screw G either inward or outward, so asto make a final and accurate adjustment by bringing the -two points to the proper distance.

When the device is applied to a compass having a pen D, as shown,'then the operator can draw circles and shade the inside or outside or both sides, as indicated in Fig. 4, without removing the point of the needle-point E from the original center. Afterinserting the point of the needle-point E into the paper the operator can open or close the legs A and B inthe usual manner until the distance between the end of the pen D and the point of the needle E is equal to the radius of the circle or segment to be drawn. After the circle is drawn the operator without changing the adjustment between the legs A and B can now proceed to shade the whole or part of the circle at the inside or the outside (see II and III, Fig. 4) or at both sides (see I, Fig. 4) by slightly pressing the leg B with one of the fingers outwardor inward. In pressing the leg inward the pen D is moved beyond the circle already drawn, and by pressing the leg outward the pen moves inside of the drawn circle. When the pressure on the leg 13 is inward, it'flexes against the tension of the spring H, and when the pressure is in the opposite direction it flexes against the tension of the spring F. Thus the point of the needle-point E is not removed from its position in the paper at the center of the circle during the shading of the circle. As shown at II in Fig. 4, the operator after first drawing a circle presses slightly on the leg B to bring the pen D to the inside of the circle drawn, so as to shade the said circle at the inside thereof at the desired part. In shading a circle or a portion thereof at the outside, as shown at III in Fig. 4, the operator presses the leg B in the opposite direction, so that the pen D moves outside of the circle, and the operator by manipulating the instrument in the usual way can thus shade a circle on the outside thereof, as indicated in the figure referred to. In a like manner both the inside and the outside of a circle or any portion thereof can be shaded, as indicated at I in Fig. 4, by successivelypressingthc leg first outward and then inward.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patent 1. A divider, compass or like instrument provided with legs, and means for maintaining them various distances apart, one of the legs being capable of flexure independent of the said means in opposite directions from its adjusted position, substantially as shown and described.

2. A drawing instrument of the class described, provided with two legs joined together, and one of which carries an inkingpen, the other being provided with a needlepoint carried by a spring capable of flexure in one direction by its own resiliency, and in the opposite direction against the tension of a second spring, substantially as shown and described.

3. A drawing instrument of the class described, provided with two legs joined together, and one of which carries an inkingpen, the other being provided with a needlepoint carried by a spring capable of fiexure in one direction by its own resiliency, and in the opposite direction against the tension of a second spring, and a device for adjusting the springs relatively to each other, as set forth.

JOHN A. BERGPTROM.

lVitnesses:

WILLIAM P. GOEBEL, Gno. C. CHENEY. 

